Cooper Companies filed a lawsuit against CIBA Vision on Apr. 10 claiming that CIBA's O2Optix contact lenses encroach on five of its patents in the USA. The patents are for innovations that control the edge characteristics of certain types of contact lenses and the unique designs of certain contact lenses. The next day Cooper filed a separate suit against CIBA seeking judicial declaration that CooperVision's Biofinity line of silicone hydrogel contact lenses do not violate certain patents held by CIBA Vision on similar products.